Process for cracking petroleum oil



Dec. 2, 1930.

R. T. PoLLocK PROCESS FOR CRACKING PETROLEUM OIL Original Filed March 9,1927 marce CoA/armste CONDE/V55( aww/nut Patented' Dee.y z, 193e ROBERTT. POLLOOK, OF vNEW' YORK, N. Y.,'ASSGNOR T0 'UNTVERSL OIL PRODUCTSparam"- orifice COMPANY, F CHICAGO, ILLINOIS, A CORPORATION OF SOUTHDAKOTA PROCESS FOR @TRACKING PJTBOLEUM OEL Original application ledMarch 9, 1927, Serial No. 173,921. Divided and this application filedNovember 14, 1929. Serial No. 407,203.

. Y Thls invention relates to lmprovements'ln process for crackingpetroleum oil and refersv more particularly to that type of process inwhich the generated vapors are subjected to reflux condensing action andthe reflux condensate, that is to say the incompletely con.-

verted oil constituents, subjected to further cracking reaction. 1 i

This application is a division of my c'opending application Serial No.173,921, filed March 9, 1927, which latter case is a continuation inpart of my application Serial No. 431,838, filed December 20, 1920.

With certain types of petroleum oil, the reflux condensate produced inthe cracking operation is more ldesirablysubjected to further crackingreaction under different temperatures and pressures than is the originaloil. By means of the present process, this reflux condensate can beseparately cracked as part of a continuous process and under different iconditions of temperature and pressure than the raw'oil. As a furtherfeature of the invention, the generated vapors are subjected to a doublereflux condensing action in which the heaviest portions of the vaporsare condensed and separately cracked while the intermediate portions ofthe vapors,'i. e., those lighter than the heaviest but not yetsufficiently cracked and therefore heavier than the lightest, areseparately condensed, subjected to furtherJ cracking under 'stilldifferent conditions of temperature and pressure.

In the drawing, the single ligure shows a somewhat diagrammatic viewpartly in side elevation and partly in vertical section of my improvedapparatus.

p Referring in detail to the drawing, A, B and C designate threeseparate furnaces. In the furnace A is mounted a heating coil 1, as'forexample,la continuous coil of 2" to 6 pipe. This coil is fed from thecharging pump 2, connected to the raw oil supply by inlet line 3 anddelivering the raw oil to the heating element through the feed line 4having throttle valve 5. The discharge side ofthe coil is connected bytransfer line 6 having throttle valve 7 to vapor chamber 8. This vaporchamber 8 is provided with liquid to a partial condenser or reduxcondenser ,16.

rllhe vapor space of this condenser is connected by pipe 17 to throttlevalve 18, nal condensercoil 19 seated in water condenser 20. The lowerend of the coil 19 is connected to the upper part of receiver 21. Thisreceiver 21 has liquid level gauge-22,v lliquid drawo pipe 23, havingthrottle valve 24 Referring back to the dephlegmator 13, to its lowerend is connected a redux condensate pipe 27, which leads to the inletside of the heating coil 28 mounted in the furnace C. A throttle valve29 is interposed in the line 27.v There is likewise interposed in thisline ya pump 30 provided at either side with valves 31 and 32, wherebythe redux condensate may be pumped under increased pressure, if desired.A by-pass line 33having throttle valve 34 is provlded for -by-passingthe pump, if desired. The discharge side of thecoil 28 is connected bytransfer line 35 having throttle valve 36 to vapor chamber 37. Thisvapor chamber 37 is provided with liquid drawoff pipe 38 controlled bythrottle valve A39. The upper end of the vapor chamber is connected byvapor pipe 40 and downwardly inclined pipe 41 having throttle valve 42,to the lower side ofa dephlegmator 43. This dephlegmater` 43 is providedwith vapor outlet pipe 44 having throttle valve 45, which 'pipe 44 isconnected to final condenser coil 46 seated in condenser box 47. f Thelower end of the coil is connected by pipe 48 having throttle valve 49to the upper part of receiver 50. This receiver 50 has liquid drawofpipe 51 controlled by throttle valve 52 and gas outlet ipe 53 controlledbythrottle'valve 54.l

- lieferring back lto the dephlegmator 13, I have heretofore stated thatthe redux condensate fromY said dephlegmator can be delivered throughpipe 27 and pump 31 or line 33 to and gas outlet pipe 25, Ahavingthrottle valvev the inlet side of the heating coil 28. It also may bedelivered elsewhere, to wit, to a suitable Areceptacle (not shown) bymeans of branch 106 having throttle valve 107. In this case the valve 29interposed in the end of ipe 27 will be closed.

eferring back to the dephlegmator 43, to its lower end is connectedreflux return pipe in which is interposed a pump 56 having at eithersidevalves 57 and 58. The pump may be by-passed by pipe 59 having valve 60.This line 55 connects to extension 55 leading to the heating coil 61seated in furnace B. This coil may be of the same construction as theother two. The discharge side of this coil is connected by transfer line63 having throttle valve 64 to an expansion or vapor chamber 65. Thisexpansion chamber 65 has a liquid drawoi' pipe 66 controlled by throttlevalve 67. It is also provided with the vapor outlet pipe 68 andconnecting downwardly inclined pipe 69 furnished with throttle valve 70and leading to the lower side of a dephlegmator 71. The upper end of thedephlegmator is connected by vapor pipe 72 having a throttle valve 73 tocondenser coil 74 seated in condenser box 75. The lower end of the 'coilis connected by pipe 76 having throttle valve 77 to -the top of receiver78. This receiver 78 has liquid drawoii' pipe 79 controlled by throttlevalve 80 and gas outlet pipe 81 controlled by throttle valve 82.

The lower end of the dephlegmator 71 is connected by reiiux condensatepipe 83 having throttle valve 84 to a second return pipe 85 leading backto the pipe 55', whereby it may be returned to the heating coil 61. Theline 83 is also provided with the branch pipe 86 having throttle valve87 connected to any suitable receptacle (not shown), whereby the l reiuxcondensate may be led elsewhere than delivered to the coil 61. In thiscase a valve 88 in the line 85 can be closed and valves 84 and 87regulated. In the pipe 85 is interposed a pump 89 having at either side,valves 90 and 91, whereby the reiux condensate may be returned to thepipe 55 under pressure. This pump may be by-passed by means of the pipe92 having throttle valve 93. A throttle valve 94 is interposed in thepipe 55.

I have heretofore stated that the reflux condensate from the pipe 55 maybe delivered to the pipe 55.. It also may be delivered elsewhere, to-wit:--to a suitable receptacle, (not shown), by means of branch 95 havinthrottle valve 96. In this case the valve 9 interposed in the end of thepipe 55 will be closed.

, Referring back to the partial condenser 16, to its lower side isconnected condensate return pipe 98. In this pipe line 98 is interposeda pump 99 .having suitable valves at either side thereof and alsoprovided with the by-pass line 100 having valve 101. The lower end ofthe pipe 98 is connected as shown at 102 to the-,line 55, provided withcontrol valve 103. The reflux condensate instead of being returned tothe pipe 55 may be delivered to a suitable receptacle (not shown) bymeans of the branch 104 having throttle valve 105. l

The process may be operated as follows:

Raw oil may be fed continuously to the heating tubes 1 where it isheated to a conversion temperature of say from 750 to 900 F., moreor-less, and from the heating tubes 1 the hot oil is passed to the vaporchamber 8 where the vapbrs separate. The vapors pass thence to the iirstvdephlegmator 13 where they can be subjected to fractionation.- Thisfractionation may be helped by the introduction of a cooling medium .inthe dephlegmator in a well known manner. The uncondensed portions arepassed to the partial condenser 16, and the still uncondensed portionsare passed to a condenser 19 Iand thence to the receiver 21. All of thei elements so far referred t'o may be maintained under the same pressureor, if desired, differential pressures may be maintained on saidelements. The reux condensate from the dephlegmator 13 may be passed tothe heating coil 28 by means of the pump 30, or of the by-pass line 33,according to the relative pressures maintained on the dephlegmator 13and the second heating coil 28. In the second heating coil 2,8 thereiiux condensate from dephlegmator 13 is subjected to furtherconditions of conversion passing thence to the vapor chamber 37 and tothe dephlegmator 43.. The condensed portions from dephlegmator 43 willpass into the condensing coil 46 and thence to the receiver 50. Thispart of the system from the coil 20 to receiver 50 may be maintainedunder the same pressure or each step of this part of the system canr`'be 'maintained under differential pressure. The pressure in this partof the system may be higher or lower than that maintained in the part ofthe system from heating coil 1 to receiver 21, and, if the differentialpressures are maintained on these two parts of the system, the pressureon a step ofthe part of the system from coil 28 to receiver 50 can behigher or lower than the pressure on the corresponding step of the artof the system from coil 1 to receiver 21. n the' other hand, andaccording to the material treated in coil 1, and also to thecharacteristics of the reflux condensate passed from dephlegmator 13through line 27 into the second heating coil 28, and also according tothe characteristics of the product which it is desired 'to produce inthe second partof the system from heating coil 28 to receiver 50, theternperature to which the reflux condensate from dephlegmator 13 issubjected in the second heating coil 28 may be higher or lower, or thesame as that to which the oil was subjected in heating coil 1.

y The reiux condensate formed in the dephlegmator 43 of the second partof the system may be passed to the heating coil 61 by means of pump 56or by-pass 59 accoiding to` the relative pressures maintained on dephlemater 43 and heating coil 61. --Here the re ux condensate will jbeheated to such under diderential pressures. in thewsame ,A manner as hasbeen heretofore described 1n relation with the first and second parts cithe system, the third part of the system from heating coil 61 toreceiver -78 can be maintained under the same presure as either one ofthe irst or second parts of the system. ln other words, thepart oit thesystem from heating coil`61 to4 receiver 78 can be main- `tained underthe same pressure as part of dit lthe system from coil 1 to-rec'eiver 21and,if

inthe same operation, the second part of the system from heating coil 28to receiver 5() -is maintained at a higher .or lower pressure than thetirst part ot the system from heating coil 1 to receiver 21, it willalso be respectively at a higher or lower pressure than the third partof the system from heating coil 61 to receiver 7 8. lin another methvodot operation, the third parteci the sysf y part oit the system, *fromheating coil-1 to hlt receiver 21up to the second part oit the'system,irom'heating coil 28 to receiver 50, the

third part of the system` from heating coil 61 to receiver 78 Ibeingthen at a pressure. intermediate those maintained on the two otherpartsoi the system. V

dll

'llhe temperature at which the various cuts` ci condensates are heatedrespectively in 28 being maintained at a higher temperature' thantheheating coil 1.,' and the oil passed .through heating*v coil 61beingsubjected to a higher temperature than that passed through coil 28.

As another method of operation, thejredux condensate subjected totreatment in heating coil 28 can be subjected to a lower temperat'urethan that at which the oil is treated in heating coil 1, and, again, theredux condensate treated in heating coil 61 can be subjected to a lowertemperature than that at' which i l the oil is treated'in 'heating coil28.

ln another method of operation, it may be desirable to treat the oil inheating coil 61 at a temperature higher than that at which the reduxcondensate from dephlegmator 13 is subjected in heating coil 28, but, atthe same time,lower than that at which the oil is subjected in heatingcoil 1. ln a further method of operation, the redux condensate fromdephlegmators 16, d3, and ilmay be subjected in heating coil 61 toaftemperature lower than that at which the redux condensate fromdephlegmator 13 is subjected in heating coil 28, and, at the same time,higher than that at which thefoil is subjected in heating coil 1. I linthe methods oi operation heretofore reierred to, and which are in no waylimiting the scope oi the invention on account of the wide variationswhich canbe brought to the method ot operation adopted to carry out theprocess, l have preferably subjected to further treatment underindependent conditions of temperatureand pressure, all the various cutsof redux condensate formed inthe operation of the recess.

. However, .in one ot the preferred methods of carrying out the process,it may be desirable to subject to further treatment only selectedfractions of the redux condensate;

u, formed in the process while'the other tracjtions are withdrawn tromthe apparatus and ldischarged to storage.. To this edect l have icaheretofore referred to valve-controlled drawl ed lines 166, 10i, 95, and86, connected respectively to the redux draw-od lines from dephlegmators13,16, i3, and ,71. By the proper manipulation oi the valves shown onllO these branch lines, the redux trom each oi i closing valve 29 online 27., the redux from v dephlegmator 13 can be withdrawnmto storage,and in this case the second part of the system from heating coil 28 toreceiver 50 will be cut od from the operation, -`Valve 97 on line 55will also be closed. At the same time,

part of the system from heating coil 28 to receiver 50 and againvsubjectthe redux condensate from the dephlegmator 43 of said second part of thesystem to further treatment in heating coil 61, while the reux condensate from the pressure condenser 16 Will be withdrawn from theprocess by opening valve 105 on branch line 104 and closing valve 103 online 55.

In another method of operation, the reflux condensates fromdephlegmators 13 and 16 can be respectively treated in heating coils 28and 61, while the reflux condensate from dephlegmators 43 and 71 areWithdrawn from the process through lines 95 and 86 respectively.

Is is not deemed necessary nto describe herein all the various methodsof operation which can be utilized to carry out the process as regardsthe treatment of reflux condensate from the various dephlegmators of theprocess upon further conditions of conversion. It is believed that theabove description of the process, together with the drawing, will enableany one skilled in the art to adopt the method of operationl best suitedto the result desired.

No specic illustration of .the pres sure and temperatures of the variousparts 'of the system have been heretofore given since they may be variedwidely-from one operation to another. The various fractions of oil canbe subjected in the various portions of the system to pressures from100` which comprises subjecting oil to a cracking.

with the oil in one of the pressure zones.

3. The process of converting heavy hydrocarbon oils into oils of lowerboiling point which comprises subjecting oil to a cracking temperatureand pressure` 1n a pressure zone, separating the high boiling fractionsof the .evolved vapors from the lower boiling fractions in the form of acondensate, subjectin the condensate while still hot to increasecracking temperature and pressure, simultaneously distilling anotherindependent body of oil, separating the evolved vapors according totheir boiling points, charging the condensate thus formed while stillhot into one of the pressure zones to co-mingle with the oil therein,and subjecting the remaining vapors while still hot to furtherfractionation to form additional condensate for the next succeedingpressure zone.v

A 4. The process of converting heavy hydrocarbons into oils of lowboiling point which comprises subjecting oil to a temperature andpressure sufficient to effect cracking thereof, separating the highboiling fractions of the evolved vapors from the low boilin fractionsinthe form of condensate, `forclng the condensate so separatedv into asucceeding zone for further cracking at an increased temperaturev andpressure, and mixing with the condensate an additional charge ofpreliminarily treated oil substantially lighter than `said oiltinitially subjected to temperature and. pressure sufficient to effectcrackingthereof and obtained from a source other than said evolvedvapors.

In testimony whereof I aHiX my signature.

ROBERT T. POLLOCK.

temperature and pressure 1n a pressure zone,

separating the 'high boiling fractions of the evolved vapors from thelow boiling fractions 1n the form of a condensate, then subjecting thecondensate while still hot to increased cracking temperature andpressure, simultaneously distilling. another independent body of oil,separating the evolved vapors according to their boiling points, andcomingling the condensate thus formed with the oil in one ofthe pressurezones.

2. The process of converting heavy hydrocarbon oils intol oils of lowerboiling point which comprises, subjecting oil to acrackmg temperatureand pressure in a pressure zone, separating the highboiling fractions ofthe evolved vapors from the lowerboiling

